Radio frequency identification (RFID) readers have been associated with mobile products, such as cellular phones, personal digital assistants, pagers and other mobile devices. Continuous active operation of typical RFID readers, however, consume significant amounts of power. Therefore, the mobile devices with which RFID readers are associated require larger power supplies and more frequent charging of the power supplies for the mobile device to continue operation than comparable mobile devices that are not associated with a RFID reader. The larger power supplies lead to larger mobile devices, which is not desirable, and frequent charging of the power supplies for the mobile device is inconvenient and reduces the lifetime of the power supply.
As such, there is a need in the industry to conserve the power in mobile devices associated with RFID readers to permit utilization of typical power supplies and typical power supply charging schedules for the mobile devices. One type of power-conserving method for RFID readers is to read only the identification portion of a RFID tag, and if the RFID reader identifies that it has previously read the tag based upon the identification portion, the RFID reader does not read the rest of the tag. While this power-conserving method is helpful, the RFID reader still consumes more power than desired.
One method utilized to conserve power in mobile devices is to measure the movement of the device and to continue active operation of the device while the movement of the device is unknown. When the movement of the device is identified, however, one or more of the subunits of the device is changed from an active operation mode to a sleep operation mode, where the sleep operation mode consumes less power than the active operation mode. The device then stays in the sleep operation mode while the movement of the device is known, then changes back to the active operation mode when the movement of the device becomes unknown. Again, while this power-conserving method is helpful, the device still consumes more power than desired because the device is in an active operation mode anytime the movement is unknown, which can be quite a bit of the time that a mobile device is used.
Thus, there is a need for techniques that permit greater conservation of power in mobile devices associated with a RFID reader so that the mobile device does not need a larger power supply or frequent power supply charging. In particular, there is a need to utilize the existing abilities of a mobile device to provide information regarding the context of the mobile device that may be utilized to optimize the power-consumption of a RFID reader associated with the mobile device.